The broad intent of the proposed study is to examine the effects of variation in the type and quality of child care centers on children's socioemotional development. This is a collaborative study involving three sites Atlanta, Georgia; Boston, Massachusetts; and Richmond, Virginia. Across these threes sites, a total of 720 children and their parents drawn from a sample of 120 child care centers (40 per site) will be studied. The children's caregivers will also participate in the study. The children will be equally divided among three age groups to permit cross- sectional analyses of results: 12-18 months, 18-36 months, and 37-60 months. The study has six specific aims: (1) To examine individual differences with respect to quality among child care centers both within and across nonprofit/profit status and regulated/unregulated status, (2) To examine individual differences among families who enroll their children in child care centers differing in type and quality as a means of controlling for parent selection of child care and examining interactions between the effects of children's home and child care environments, (3) To examine individual differences among children in the effects of child care based on their history of child care experience, gender, and temperaments, (4) To examine interactions among the three systems defined by characteristics of children, of families, and of child care centers. (5) To examine the influence of state variation in child care regulations on the quality of care offered in each study site as well as on the development of children, and (6) To inform theoretical issues about the role of experience in child development. We hypothesize that quality of care, assessed with observational measures of program quality and state-level measures of the stringency of child care standards, rather that the children's age of entry into care and amount of time in care will emerge as the primary predictor of children's socioemotional development. We further hypothesize that children's family backgrounds will interact with the type and quality of care such that lower resource families will use lower quality care, creating significant interactions between child care and home environments as they affect development.